NOTE: see also the update to this article.
Whether due to unfavorable weather conditions or inevitable spring constraints, there are some fields where corn has emerged before the planned preemergence herbicides could be applied. Many preemergence corn herbicides can also be applied early postemergence in corn. Axiom, Balance, Define and Epic herbicides are exceptions and can only be applied prior to corn emergence. The table below lists some of the preemergence corn herbicide products that can also be applied postemergence, as well as the recommended maximum plant heights or growth stages at application. Products listed include only those that do not require specific, herbicide tolerant corn hybrids.
Iowa State University
Schaefer, Kristine J. P., "Delayed herbicide options for emerged corn" (2004). Integrated Crop Management News. 1533.
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